Optical transmission device and optical transmission method

Abstract

There is provided an optical transmission device which includes a determiner, a convertor, and a switch. The determiner determines whether a frame includes a fixed stuff byte area or not when the frame is received from a first network, where the frame includes a payload area for storing client data and the fixed stuff byte area is for storing fixed data. When the determiner determines that the frame includes the fixed stuff byte area, a convertor to convert a fixed stuff byte area into the payload area and a switch switches a clock frequency from a first clock frequency used in the first network to a second clock frequency used in a second network when the frame including the converted fixed stuff byte area is output to the second network on the basis of the clock frequency as a reference.

What is claimed is: 
     
       1. An optical transmission device for receiving first data from a first network and transmitting second data corresponding to the first data to a second network comprising:
 a determiner configured to determine whether a frame includes a fixed stuff byte area or not when the frame is received from the first network, the frame including a payload area for storing client data, the fixed stuff byte area being for storing fixed data; 
 a convertor configured to convert the fixed stuff byte area into the payload area when the determiner determines that the frame includes the fixed stuff byte area; and 
 a switch configured to switch a clock frequency from a first clock frequency used in the first network to a second clock frequency used in the second network when the frame including the converted fixed stuff byte area is output to the second network on the basis of the second clock frequency as a reference. 
 
     
     
       2. The optical transmission device according to  claim 1 , wherein the determiner determines that the frame includes the fixed stuff byte area when a data value stored in an overhead area of the frame is a specific value. 
     
     
       3. The optical transmission device according to  claim 1 , wherein the determiner determines that the frame includes the fixed stuff byte area when a predetermined position in the payload area of the frame is vacant. 
     
     
       4. The optical transmission device according to  claim 1 , further comprising a detector configured to detect a clock frequency used in the first network, wherein the switch switches the clock frequency from the detected clock frequency to a third clock frequency used in the second network, the third clock frequency corresponding to the detected clock frequency. 
     
     
       5. The optical transmission device according to  claim 2 , further comprising a detector configured to detect a clock frequency used in the first network, wherein the switch switches the clock frequency from the detected clock frequency to a third clock frequency used in the second network, the third clock frequency corresponding to the detected clock frequency. 
     
     
       6. The optical transmission device according to  claim 3 , further comprising a detector configured to detect a clock frequency used in the first network, wherein the switch switches the clock frequency from the detected clock frequency to a third clock frequency used in the second network, the third clock frequency corresponding to the detected clock frequency. 
     
     
       7. The optical transmission device according to  claim 1 , further comprising:
 a stuff processor configured to store the client data in a stuff byte area provided in the frame when there is a frequency deviation between the first clock frequency and a third clock frequency of the second network as a client network to which the client data is transmitted; and 
 an adjuster configured to adjust an amount of the client data to be stored in the stuff byte area with a specific rate when the fixed stuff byte area is converted to the payload byte area by the convertor, the specific rate being a proportion of data overflowing from the payload byte area to the frame in which the fixed stuff byte area is not inserted. 
 
     
     
       8. The optical transmission device according to  claim 2 , further comprising:
 a stuff processor configured to store the client data in a stuff byte area provided in the frame when there is a frequency deviation between the first clock frequency and a third clock frequency of the second network as a client network to which the client data is transmitted; and 
 an adjuster configured to adjust an amount of the client data to be stored in the stuff byte area with a specific rate when the fixed stuff byte area is converted to the payload byte area the convertor, the specific rate being a proportion of data overflowing from the payload byte area to the frame in which the fixed stuff byte area is not inserted. 
 
     
     
       9. The optical transmission device according to  claim 3 , further comprising:
 a stuff processor configured to store the client data in a stuff byte area provided in the frame when there is a frequency deviation between the first clock frequency and a third clock frequency of the second network as a client network to which the client data is transmitted; and 
 an adjuster configured to adjust an amount of the client data to be stored in the stuff byte area with a specific rate when the fixed stuff byte area is converted to the payload byte area by the convertor, the specific rate being a proportion of data overflowing from the payload byte area to the frame in which the fixed stuff byte area is not inserted. 
 
     
     
       10. The optical transmission device according to  claim 4 , further comprising:
 a stuff processor configured to store the client data in a stuff byte area provided in the frame when there is a frequency deviation between the first clock frequency and a third clock frequency of the second network as a client network to which the client data is transmitted; and 
 an adjuster configured to adjust an amount of the client data to be stored in the stuff byte area with a specific rate when the fixed stuff byte area is converted to the payload byte area by the convertor, the specific rate being a proportion of data overflowing from the payload byte area to the frame in which the fixed stuff byte area is not inserted. 
 
     
     
       11. An optical transmission method comprising:
 determining whether a frame includes a fixed stuff byte area or not when the frame is received from a first network, the frame including a payload area for storing client data, the fixed stuff byte area being for storing fixed data; 
 converting the fixed stuff byte area into the payload area when the determining determines that the frame includes the fixed stuff byte area; and 
 switching a clock frequency from a first clock frequency used in the first network to a second clock frequency used in a second network when the frame including the converted fixed stuff byte area is output to the second network on the basis of the second clock frequency as a reference.